C298Main Board - Epson Stylus COLOR 760 Service Manual

EPSON Stylus COLOR 760

2.2.2 C298MAIN Board

The logic circuit of the C298MAIN is composed of the following:
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Logic line (CPU, ASIC, DRAM, EEPROM, and so on)
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Various motor control/driver circuits (CR motor, PF motor )
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Head control/driver circuits
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Interface control (parallel I/F, USB I/F)
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Sensor circuits
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Timer circuits
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Reset circuits
This main board is mainly different form other models in the following two
points.
o
Use of the 3.3V chips in the logic circuit
The 3.3 V regulator (IC9) on the C298MAIN produces 3.3 V by pressuring
down the 5.5 VDC, also generated on this board, to drive several chips.
See the table below that separately shows the chips driven by the +5V and
+3V.
Table 2-9. 3.3V Drive Chips & 5.5V Drive Chips
+5V
Sensors
I/F Circuit
PNL Board
Slave CPU
o
Use of the slave CPU
Since the CR motor and PF motor of this printer are DC motors, the slave
CPU is attached on the main board in addition to the CPU and ASIC. This
slave CPU, serving to control the DC motors only, reduces duty of the CPU
and ASIC for faster data processing.
See Figure 2-17 for the C298MAIN board block diagram.
Operating Principles
3.3V
CPU
ASIC
P-ROM
D-RAM
Electrical Circuit Operating Principles
Figure 2-17. Block Diagram for the C298MAIN Board
Revision C
43